DESCRIPTION

When <paths> are not given, this command switches branches by
updating the index, working tree, and HEAD to reflect the specified
branch.

If -b is given, a new branch is created and checked out, as if
git-branch(1) were called; in this case you can
use the --track or --no-track options, which will be passed to git
branch. As a convenience, --track without -b implies branch
creation; see the description of --track below.

When <paths> or --patch are given, this command does not switch
branches. It updates the named paths in the working tree from
the index file, or from a named <tree-ish> (most often a commit). In
this case, the -b and --track options are meaningless and giving
either of them results in an error. The <tree-ish> argument can be
used to specify a specific tree-ish (i.e. commit, tag or tree)
to update the index for the given paths before updating the
working tree.

The index may contain unmerged entries after a failed merge. By
default, if you try to check out such an entry from the index, the
checkout operation will fail and nothing will be checked out.
Using -f will ignore these unmerged entries. The contents from a
specific side of the merge can be checked out of the index by
using --ours or --theirs. With -m, changes made to the working tree
file can be discarded to recreate the original conflicted merge result.

OPTIONS

-q

--quiet

Quiet, suppress feedback messages.

-f

--force

When switching branches, proceed even if the index or the
working tree differs from HEAD. This is used to throw away
local changes.

When checking out paths from the index, do not fail upon unmerged
entries; instead, unmerged entries are ignored.

--ours

--theirs

When checking out paths from the index, check out stage #2
(ours) or #3 (theirs) for unmerged paths.

-b

Create a new branch named <new_branch> and start it at
<start_point>; see git-branch(1) for details.

-t

--track

When creating a new branch, set up "upstream" configuration. See
"--track" in git-branch(1) for details.

If no -b option is given, the name of the new branch will be
derived from the remote branch. If "remotes/" or "refs/remotes/"
is prefixed it is stripped away, and then the part up to the
next slash (which would be the nickname of the remote) is removed.
This would tell us to use "hack" as the local branch when branching
off of "origin/hack" (or "remotes/origin/hack", or even
"refs/remotes/origin/hack"). If the given name has no slash, or the above
guessing results in an empty name, the guessing is aborted. You can
explicitly give a name with -b in such a case.

--no-track

Do not set up "upstream" configuration, even if the
branch.autosetupmerge configuration variable is true.

When switching branches,
if you have local modifications to one or more files that
are different between the current branch and the branch to
which you are switching, the command refuses to switch
branches in order to preserve your modifications in context.
However, with this option, a three-way merge between the current
branch, your working tree contents, and the new branch
is done, and you will be on the new branch.

When a merge conflict happens, the index entries for conflicting
paths are left unmerged, and you need to resolve the conflicts
and mark the resolved paths with git add (or git rm if the merge
should result in deletion of the path).

When checking out paths from the index, this option lets you recreate
the conflicted merge in the specified paths.

--conflict=<style>

The same as --merge option above, but changes the way the
conflicting hunks are presented, overriding the
merge.conflictstyle configuration variable. Possible values are
"merge" (default) and "diff3" (in addition to what is shown by
"merge" style, shows the original contents).

-p

--patch

Interactively select hunks in the difference between the
<tree-ish> (or the index, if unspecified) and the working
tree. The chosen hunks are then applied in reverse to the
working tree (and if a <tree-ish> was specified, the index).

This means that you can use git checkout -p to selectively discard
edits from your current working tree.

<branch>

Branch to checkout; if it refers to a branch (i.e., a name that,
when prepended with "refs/heads/", is a valid ref), then that
branch is checked out. Otherwise, if it refers to a valid
commit, your HEAD becomes "detached" and you are no longer on
any branch (see below for details).

As a special case, the "@\{-N\}" syntax for the N-th last branch
checks out the branch (instead of detaching). You may also specify
- which is synonymous with "@\{-1\}".

<new_branch>

Name for the new branch.

<start_point>

The name of a commit at which to start the new branch; see
git-branch(1) for details. Defaults to HEAD.

<tree-ish>

Tree to checkout from (when paths are given). If not specified,
the index will be used.

Detached HEAD

It is sometimes useful to be able to checkout a commit that is
not at the tip of one of your branches. The most obvious
example is to check out the commit at a tagged official release
point, like this:

$ git checkout v2.6.18

Earlier versions of git did not allow this and asked you to
create a temporary branch using the -b option, but starting from
version 1.5.0, the above command detaches your HEAD from the
current branch and directly points at the commit named by the tag
(v2.6.18 in the example above).

You can use all git commands while in this state. You can use
git reset --hard $othercommit to further move around, for
example. You can make changes and create a new commit on top of
a detached HEAD. You can even create a merge by using git
merge $othercommit.

The state you are in while your HEAD is detached is not recorded
by any branch (which is natural --- you are not on any branch).
What this means is that you can discard your temporary commits
and merges by switching back to an existing branch (e.g. git
checkout master), and a later git prune or git gc would
garbage-collect them. If you did this by mistake, you can ask
the reflog for HEAD where you were, e.g.

$ git log -g -2 HEAD

EXAMPLES

The following sequence checks out the master branch, reverts
the Makefile to two revisions back, deletes hello.c by
mistake, and gets it back from the index.

At this point, git diff shows the changes cleanly merged as in
the previous example, as well as the changes in the conflicted
files. Edit and resolve the conflict and mark it resolved with
git add as usual: